Marine Species: the Seamoth

The humble seamoth is burdened with the Latin name Pegasidae, a mash-up of Pegasus, the winged stallion born of Poseidon, Greek god of the sea, and Medusa, the snake-haired gorgon. Even its common name calls to mind a Godzilla-style nemesis, one that may explode into the air from the ocean depths, the thunderclap of its terrible wings striking fear into hearts of anyone nearby.

In fact, seamoths are adorable little creatures. Divers will often find them in monogamous pairs. They scuttle across sandy, rubbly substrate and suck eggs, worms, copepods, isopods, and other tiny invertebrates into their snouts.

There are five species of seamoth, ranging in length from three to eight inches (8 to 20 cm). Instead of scales, their bodies are sheathed with bony plates that they molt every week or so to rid themselves of parasites. This rather Medieval exoskeleton has earned them another common name: dragonfish.

So how did the name “seamoth” come about? In addition to their elongated, moth-shaped bodies, they have wing-like pectoral fins, which they unfurl when threatened or when they want to move quickly. They use the tips of these pectoral fins as sort of steadying hands as they amble about on “legs” of scythe-shaped pelvic fins. The overall effect is a bit like a man with stubby legs grasping at seatbacks as he makes his way through a moving train.

Where to find a seamoth

Seamoth habitat spans the tropical Indo-Pacific, including popular dive destinations like Tanzania, the Maldives, western Thailand, Indonesia, Malaysian Borneo and the southern Philippines. Sadly, the International Union for Conservation of Nature (IUCN) lists at least one species of seamoth as vulnerable. Trawlers sweep them up as bycatch or they are purposely collected for use in traditional Chinese medicines and for sale in the aquarium trade.

You can find seamoths in coastal waters at depths from around 10 to 295 feet (3 to 90 meters). Since they are bottom-dwellers, they prefer sand, rubble and seagrass, where they can rely on their mottled armor as camouflage. For this reason, you’ll see them most often in areas where muck-diving is popular: Lembeh, Indonesia; Puerto Galera, Philippines; Milne Bay, Papua New Guinea; Mabul, Malaysia; Nudi City, Tanzania, and so on.

How to find a seamoth

From far away, seamoths can look like rocks, algae or sea debris. Because of their small size and camouflage, the key first step to spotting one is to dive slowly. Finning quickly around a dive site won’t net much. Become familiar with the shape of the seamoth most prevalent where you’re diving — long and thin for slender seamoths, and chunkier with a long snout for a common seamoth. Ask a local Divemaster for guidance.

Get close to the bottom and maintain good buoyancy. Use proper fin technique to avoid kicking up sand or silt. Look for anything that appears to be an eye or, more specifically, two sets of eyes, since seamoths generally hang out in pairs.

Once you do find one, you’ll quickly learn an annoying seamoth quirk: They skittishly turn away from divers, so you’ll spend a lot of time gazing at seamoth butt. It’s worth the effort, though, to witness these strange creatures “fly” across the sand.

Pegasus Sea Moth from liquidguru on Vimeo.

Guest author Christina Koukkos is a New York-based freelance writer and editor. She covers scuba diving, responsible tourism, off-beat destinations, cultural travel and other topics. She’s a certified PADI dive instructor and MSDT as well as an amateur underwater (and topside) photographer. Learn more about her on her website, on her blog, on Instagram or Twitter.